Seafish Insight Blog: Why it's OK to eat North Sea and West of Scotland haddock

Since around 2007, spawning stock biomass (SSB) has been above
the reference point for maximum sustainable yield (MSY) with
fishing mortality being lower than the MSY reference point (the
basis for a well-managed sustainable fishery).

During the 2016 stock assessment an error in the assessment
model was discovered. In addressing this matter, fisheries
scientists at the International Council for the Exploration of the
Seas (ICES) corrected the statistical model, reviewed the reference
points for fishing mortality and reassessed the advice.

The reassessment showed that the spawning stock biomass had been
above the reference point for maximum sustainable yield (MSYB
trigger) for the period 2002 until 2015, but the target fishing
mortality (or fishing pressure), which is the rate at which the
fish are harvested, was set too high at approximately twice the
rate it should be for Maximum Sustainable Yield (FMSY). The
reassessment took into account the consistently lower levels of
recruitment of young fish since 2000. When implemented, such
a rate would enable better survival of haddock to maturity and
hence potentially better reproduction and improved
sustainability.

In the 2016 reassessment, this stock was assessed by ICES to be
in the 'at risk' category; this means there was a risk of the
spawning stock biomass being below the level required to sustain a
fishery while the fishing pressure was also too high. The ICES
advice for total catch in 2017 was 39,461 tonnes which is
consistent with maximum sustainable yield (F at FMSY of 0.19 in
2017) and includes 6071 tonnes which was expected to have been
discarded.

However, all vessels in the North Sea in 2017 using gear of 100
mm or more (whitefish) and 80-99 mm gear (Nephrops) will need
to land all haddock, and vessels targeting cod, haddock,
whiting and saithe in West of Scotland waters will also need to
land all their catches of haddock. These fisheries account for most
of the haddock catch so that provided The Landing Obligation is
adhered to we can expect the total catches to be close to the
agreed Total Allowable Catch (TAC).

The EU-Norway agreed TAC is 39,409 tonnes. If this number is the
total catch then the projected spawning stock biomass in 2018 is
expected to be 205,595 tonnes which is above the reference point
for maximum sustainable yield (MSYBtrigger) of 132,000 tonnes
and not in the at risk category.

We would need to catch 119,463 tonnes in 2017 to drive the stock
to MSYBtrigger in 2018. The above results suggest that there is
some margin for error; the main imperative is to aim for a lower
rate of fishing mortality, which should enhance future
sustainability.